By-pass system for piston pumps



1,416,731, tel may 23, 1922.

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F. MARTIN. BY-PASS SYSTEM FOR PESTGN PUMPS.

' Marsman man senza, i920.

a1,41. 6,731 l Patentd May 23, 1922.

2 SHEETS-SHEET 2.

` pump;

FRIEDRICH MARTIN, 0F ESSEN, GERMANY, ASSIGNOR T0 FRIED. KRUPP AKTIEN-GESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

BY-PASS SYSTEM FOR PISTO'N PUMPS.

To all whom tmgzy concern.'

Be it known that I, FRIEDRICH MARTIN, residing at Essen, Germany, acitizen of the German Republic, have -invented a certain new and usefulImprovement in By-Pass Systems 'for Piston Pumps, (for which I havefiled anapplication in Germany May 3rd, 1917,) of which the following isa specication. f

. The present invention relates to a by-pass system for piston pumps.Such systems have, as is well known, the purpose of avoidp ing astoppage ofthe'engine serving to drive the pump, when the latter is nolonger required to deliver liquid'under pressure into the line. Thefluid 1n by-pass systems of the known art flows from the pressurechamber of the pump through the by-pass system into the suction chamberand from the latter through the pump cylinder back. to the pressurechamber. But -by-pass systems of that kind are not suitable for multiplecylinder piston pumps with driven shafts and provided with a starting ordistribution valve slide, common for all the pump cylinders andpartaking in the revolution of the driving shaft during the operation'ofthe pump. The reason being that when such a valve slide-is used, thevalve passages can naturthe pressure chamber through the valve passages.As now, during circulation, the same fluid particles have to repeatedlypass through the valve passages, the temperature of the" circulatingfluid must at last rise to -an unpermissiblevhigh temperature. Thepresent invention has now for its object to produce a by-passl system`of simple, construction forpump's of the described art. On theaccompanying drawing a pump is illustratedwith a by-pass systemrepresenting one embodimentof the present invention, in which Fig. lshows a longitudinal sectiony of the Fig. 2 a cross section of Fig. 1along 2 2 seen fro-m the left and Fig. 3 a cross section of Fig. l alongthe line 3 3, 4also seen from the left.

The pump is provided with a stationary cylinder housing A, with ninecylinders a arranged parallel toeach other and at the Specification ofLetters Patent.y 'i

Asa consequence, the

u Patented May 23, 1922,

Application mdpseptembe 25, 1920. serial No. 412,895.

`same distance'fromy the driving shaft B. In

each of the cylinders a runs a piston C, which is in positiveconnection'with the driving shaft B through the intermediary of aso-'called inclined dlsc gear, and in such a manner that the pistonreceives a reciprocative movement from the rotation of the shaft. Thehousing A is provided with cylindrical suction passage az arrangedcoaxially with the shaft B and a pressure chamber a3 likewise cylinofconstant stroke lengthdrical and coaxial with the shaft B andsurrounding the valve slide D which is fixedly attached to the shaft B.The valve slide isprovided with two ports d and d? of crescent shape andsymmetrically arranged on the contact face of the slide, see Fig. 3, theone port d being in constant communication with the pressure chamber a3,while the other al? leads to a suction passage a2 which is in constantcommunication with an inner chamber als of the starting slide. From eachof the cylinders a a passage a4 leads to the slide surface through whichthe working chamber of the cylinder during the rotation of the slide Dcan alternatively get into communication with one of the twocrescentshaped vpassages d and d2. A by-pass port a5 branches off fromeach of the passages a4 towards the side that is situated away from thevalve slide D. All the by-pass ports a5 open against the surface e4' ofa rotary slide E which is movable by means of a shaft E .carried in thehousing A coaXially with the hand, with certain angular position of the`yrotary slide, one of the by-passports a5 tion with the centralchambere2 through a corresponding passage e3, while on the other hand,after the slide has been turned a ceras shown on the drawing, eachstands 1n connectain angle ea'ch by-pass .port a5 becomes closed by abridge between the passages e3.

los

During the correct running of the pumps.

the rotary slide E is so adjusted that it closes the by-pass port a5.rIhe fluid then Hows from the suction pipe A through the central chambere2V of the rotaryslide E and the suction passage a2 into the inner cham-`ber d of the starting slide D and from thenbecomes heated during itspassage byass ports a of t e rotary slide. The main portion of thev fcecross section' sufficiently es and al5 'and the portions of 4c 'I claimis': v 1'. A deviceof the classdescribedcomf p nsmg a drivlng-,shafh -amliltiplicityof4 through the comparative passages. But as thev sameduring the proper running of'jthepump only once passages by entering andleaving, the rise in emperature remains below the permissible If the umphasto work with". a `movey'ment of t efluid throuh the by-'pass sys- Ybe adjusted so that the paagese, asjshown on tem, then the rotary sli eE' hasto make connection between the the drawing,

and the central chambers.

uid then enters the cylinders a; during the suction stroke4 on the pathe, the ports and all the fluid returns-the same :wayto t e suctionchamber, during the pressure i stroke. y As there is no difficulty inmaking the orilarge both 'of the passagespassages a* which are situatedbetween the ports-1al and no "iiiculty 1n avoiding any unpermiibleincrease in tem erature'during --the movement'of the fluid through theby-passgsys'- tem. v v v Having thus described my invention, what lynarrowr valvev vfluid particles,

vflow through theI v empty" valve the cylinders a', there will bevcylinders, av starting slide commonto all cylinders 'and partaking inthe rotary move-V 4I ment of the driving shaft, a suction chamber, acontrol member' 4provided with. ports for providing independentcommunication between the cylinders and the suction cham- 4 ber and,said control member being rotatable vI5. .for closing said independentcommunica tions. Y.

" 2. A device of the class described, comprising a drivingshaft, amultiplicity of c linders, a rotary slidevalve common to 5I al thecylinders, said valve bein opera- I tively connected to the driving lsaft and partaking in its rotary movement, a suction chamber, a secondslide member provided Vwith a multiplicity of ports for providingindependent lcommunication between sai suction chambers and 'thecylinders, saidl second slide member being rotatable for controllingsaidl independent' communications. 3.`- In a 'pump having a multi licityof 6I :cylinders and lpistons' working t erein, a

s aft for ldriving the istons, ,ai suction chamber and a pressurechamber common rto lall-theicylinders and a rotaryfslide'valveositi'velyf connected to said drivin .shaft 'Il or controllingthejcommunication' tween said cylinders and theg'suction chamber' andthe p'resmlre-chamber alterinatively',A abypass system comprising"'ajplurality of ports for providin communicatfonbetween the 'Il suctioncham r'andeach f said-cylinders I lindependently-of said rotargfslidevalve and an a justable valve common'to all said ports" Afor closingthem.-I l f The foregoing specification signed at Es- 8l sen, Germany,this 17th day of June, 1 920.

FRIEDRICH MARTIN. .'IlPresence'ofl HANs GorrsMANN, v

J oHaNN Daems.

